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Chastetree (Vitex agnus-castus)

Chastetree (Vitex agnus-castus)

Best for

Fewer PMS symptoms

Barely detectable 20–40 mg/day 8–12 weeks 1 study, n=170 #2 of 10 studied

  • 4 papers
  • 1 of 16 outcomes
  • 1 positive

Chastetree barely improves premenstrual syndrome symptoms, with evidence strongest for PMS and too limited to support noticeable benefits across other outcomes.

Median effective dose, most-studied outcomes

  • Ease the overall PMS burden 20 mg 12 wk
Full protocol, 1 outcomes

Risk, worst reported severity

  • Acne mild
  • Multiple abscesses mild
  • pramipexole moderate
All 9 events and interactions

What chastetree (vitex agnus-castus) actually does

Outcome Effect Evidence Dose Time Rank
Early research 1
Fewer PMS symptoms Barely detectable PMS can bring physical and emotional symptoms in the days before a period.
trivial 		2 RCTs 1 papers · n=170 20–40 mg 8–12 wk #2 /10

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

The available PMS trial used 20 mg daily for 12 weeks. It found only a trivial change in overall PMS burden, so increasing the dose does not have evidence behind it as a way to produce a bigger result. 1

When and how long

Take it consistently each day rather than only when symptoms start. The trial assessed a full 12-week course, which means the evidence does not tell you that occasional use works. 1

Forms & standardisation

Look for a product that clearly identifies Vitex agnus-castus fruit extract and states the amount per daily serving. The PMS trial tested a standardized fruit extract, not tea, whole berries, or a vague proprietary blend. 1

Studied range, by outcome

Outcome Studied range Median effective Duration Evidence
Ease the overall PMS burden 20 mg 20 mg 12 wk 1 paper 2 sig. endpoints

Adverse events and drug interactions

Safety events

Acne mild
Multiple abscesses mild
Intermenstrual bleeding mild
Urticaria mild
Early menstrual period mild
Gastric upset mild
nausea mild
spotting mild

Drug interactions

pramipexole moderate additive
Buy well

Recommended Chastetree (Vitex agnus-castus) products

Real products that dose Chastetree (Vitex agnus-castus) where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Chastetree (Vitex agnus-castus) dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

In context

What this is and how it works

  • One randomized trial (n=170) found a barely detectable improvement in four premenstrual syndrome endpoints.1
  • Four papers reviewed here span 16 outcomes, with only one early-tier claim supporting PMS symptom relief.
  • Evidence applies primarily to people with premenstrual syndrome; broader benefits remain unestablished.

Chastetree, also called vitex, comes from the dried fruit of a Mediterranean shrub. People use fruit extracts in capsules or tablets, usually in the weeks and months leading up to their periods. The clinical research for PMS is still thin, so the label hype runs ahead of what the trial result shows. 1

Chastetree appears to interact with dopamine signaling, the brain-to-pituitary messaging system that helps control prolactin release. Think of dopamine as a hand on a hormone faucet: when the signal presses down, it can turn down prolactin output, a pathway researchers have explored in PMS. 1

Bottom line

Chastetree is a reasonable topic to discuss with a clinician if PMS disrupts your life and you want to explore a botanical option, but set the bar low. The available trial found only a trivial benefit, not the kind of change that reliably transforms a difficult cycle. 1 Avoid self-experimenting if you have unexpected menstrual bleeding, and review medications with a clinician or pharmacist first.

Frequently asked

Common questions

Does chastetree help with PMS?

A 12-week randomized trial found only a barely detectable improvement in overall PMS burden with chastetree. That is not strong enough evidence to expect a noticeable difference in cramps, bloating, or mood symptoms. 1

How long does chastetree take to work for PMS?

The available PMS trial assessed daily use over 12 weeks, or about three menstrual cycles. It does not support judging the supplement after only a few days. 1

What is Vitex agnus-castus?

Vitex agnus-castus is the botanical name for chastetree, a shrub whose dried fruit is used in supplements. Research has mainly examined it for premenstrual symptoms. 1

Can chastetree affect your period?

Yes. Mild reports include early periods and bleeding between periods. Stop and speak with a clinician if your bleeding pattern changes unexpectedly.

Sources

Sources

  1. 1. Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study (2001) ↑

Generated August 27, 2026

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